1. Field of the Invention
This invention relates in general to a method and apparatus for applying dental treatment fluid, and in particular to a method and apparatus wherein anesthetic or other fluid is applied to the gums by means of a tray which surrounds the teeth and gums.
2. Description of the Prior Art
Dentists normally have their patients on a program whereby their teeth are thoroughly cleaned periodically, such as every six months. If the cleaning process is performed properly, it can be very painful because it is necessary to scrape away foreign material from between the teeth and the gums. Consequently, anesthesia is sometimes applied to the gums, usually by means of hypodermic injection. Such injections of anesthetic are in themselves uncomfortable or painful, as well as being time consuming and not completely effective in anesthetizing the proper portions of the gums.
The method and apparatus of the present invention overcome the above mentioned difficulties, and allow quick, painless and thorough anesthetization of the gums by using a tray shaped to conform to the jaw. The tray has an inflatable seal which seals against the gums so that a vacuum can be applied to suck out saliva from between the teeth and gums. The resultant vacuum in the tray is used to draw a liquid topical anesthetic back into the tray and beneath the gums where the saliva was previously located.
There are several prior known devices and methods for dental treatment which generally include applying a fluid to the teeth and gums by means of a tray, although none of them disclose the present invention. For example, U.S. Pat. Nos. 803,474 and 803,475, both to Dennis and both issued Oct. 31, 1905, show a reservoir shaped to conform to the configuration of the gums and teeth, but there does not appear to be a firm seal between the reservoir and gums. Attached to the reservoir are one or more tubes connected to a compressible bulb which contains the treatment fluid. By alternately compressing and releasing the bulb, the teeth and gums are irrigated with the treatment fluid. The '475 patent mentions that the device may be used as a desensitizer for the gums before mounting crowns and bridges.
Another example of an irrigation type tray is shown in U.S. Pat. No. 1,500,107 to Chandler, issued July 8, 1924. The Chandler device is not designed to seal around the gums.
U.S. Pat. No. 1,371,029 to Jennings, issued March 8, 1921, shows a dental applicator tray having relatively thin and flexible walls for better engaging the teeth and gums, thereby enabling a better vacuum to be formed within the reservoir for drawing impurities or pus from the gums.
Another tray designed to seal against the gums is shown in U.S. Pat. No. 3,380,446 to Martin, issued Apr. 30, 1968. Martin shows a tray which provides a liquid seal at the gums above the line of the teeth. It is mentioned in the patent that it was found necessary to form trays for each person to be treated. In contrast, the inflatable seal of the present invention allows a single tray to be used for a range of different jaw sizes.
U.S. Pat. No. 2,311,158 to Conway et al., issued Feb. 16, 1943, shows a device for making impressions of the gums for the manufacture of dentures. The device has inflatable tubes which apply pressure to a rapidly setting plastic material in directions normal to the anterior and posterior seal areas of the jaw so as to obtain uniform impressions of those areas in the plastic material.
Other patents of general interest are U.S. Pat. Nos. 1,934,688 to Ackerman, issued Nov. 14, 1933; 3,060,935 to Riddell, issued Oct. 30, 1962; 3,481,329 to Warren, issued Dec. 2, 1969; 3,489,141 to Warren, issued Jan. 13, 1970; and 3,772,790 to Swan-Gett et al., issued Nov. 20, 1973.